Hostnames not showing up in DHCP

I work with a school system, and we have a web filter box where we can monitor students' internet usage. When we find abuse, we look up the IP address of the abuser in the DHCP management console, get the hostname of the computer, and thus locate the offender (the computers are given a hostname that includes the classroom number). However, often when we look up an IP address, the hostname does not appear, and we suspect some of the students have found a way to hide the hostname. We are on a Novell Netware 6.5 network. Does anyone know how these students could be doing this?

re: Hostnames not showing up in DHCP

My personal favorite is to log in, change the login client to not run scripts, and then log back out.

Not too sure how to reset that as an admin, though I'll keep looking (and for other possible ways to bypass).

Just to cover the basics - I assume they don't have the ability to use the hostname command to reset it?

re: Hostnames not showing up in DHCP

I don't think they can change the hostname using that command. I have tried that and cannot make it work. They may know something I don't, however.

I'm not following you on the script thing. I did that on a student machine and the hostname is still showing up. Can you give me more detail?

re: Hostnames not showing up in DHCP

you cant see IP add. in DHCP network.you can identified them only by host name.because DHCP automatically provide the IP add. in the network with in seconds.

re: Hostnames not showing up in DHCP

I don't know if this will help. But many times students may use a batch file to use ipconfig/ release and the ipconfig/ renew to connect to the network again, but i don't know if this may affect the hostname server getting a response from the computer.

Also students maybe running a portable firewall, I myself as a student did this for awhile and i can block any connection to my computer. From other students trying to hack me or the DHCP server at my school gathering the hostname from my computer. But i never knew if it actually worked though. I'd give it a try.

Yoda